Nonclassical correlations and quadrature squeezing of photons in anisotropic quantum Rabi-Stark model

Abstract: This study investigates nonclassical effects of photons in the anisotropic quantum Rabi-Stark model by using a quantum dressed master equation. We analyze second- and higher-order correlation functions, and demonstrate that the nonlinear Stark coupling significantly modulates photon statistics, inducing distinct and tunable photon antibunching and bunching effects. Successive transition signatures of correlation functions provide a potential experimental probe for predicting quantum phase transitions. We further reveal that Stark coupling provides direct control over photon squeezing, achieving significant enhancement and suppression. These findings not only uncover rich nonclassical phenomena in the anisotropic quantum Rabi-Stark model but also establish the nonlinear Stark coupling as a crucial new dimension for quantum detection. It may open a new avenue for precise manipulation of strongly coupled light-matter systems, with potential applications in quantum information processing and quantum-enhanced technologies.